Brake tester



Sept. 5, 1933 G. A. WEIGT 1,925,239

BRAKE TESTER Filed Nov. 21, 1930 I INVENTOR. 650 665 h E/e-W" A TTORNEYS.

wr Wm pendent upon the skill of the Patented Sept. 5, 1933 UNITED STATES BRAKE 'rns'mn George A. Wcigt, Fresno, Calif;

Application November 21, 1930 Serial No. 497,20}

4 Claims. (Cl. 265-1) My invention relates generally to brake testing apparatus and more particularly to apparatus suitable for testing the brakes on automobiles and the like.

Heretofore, in testing automobile brakes to determine the distribution of the braking. force on the different wheels of the automobile, it has been a common practice to that its wheels are out of contact with the ground. While the car is in this position, the brake pedal is partially depressed to cause the brakes to be applied relatively lightly. Then by rotating the traction wheels manually it could be Qroughly determined whether or not the braking force was properly distributed. This method was obviously unreliable, since the accuracy of the test depended'entirely on the judgment of the person making the test. a

For testing the total amount oi. braking force applied to the wheels, it has been a common practice to measure the distance required to bring the car to a stop after the car has been broughtup to a definite speed. This method of testing brakes is also very inaccurate since the results are decondition 01 the road and upon the amount oi force applied to the brake pedal.- While laboratory equipment has been designed for testing brakes, such equipment is. ordinarily not accessible to the average automobile owner.

It is one object of my invention to provide novel apparatus for testing brakes which is reliable and p which is convenient to use.

s. testing brakes which is Another object is to provide apparatus for compact and simple in construction.

These and other objects and advantages are attained in the embodiment of the invention illustrated in the accompanying drawing, in which:

Fig. l is a plan view of a brake tester constructe ed in accordance with this invention.

2 is a side view of the device shown in 1.

Fig. 3 is a view illustrating the manner in which the device can be used to determine the braking force applied to an automobile wheel.

Fig. 4 illustrates a clamping device for holding a brake pedal depressed as it appears when in use.

Briefly, the brake tester of this invention comprises a leverage mechanism adapted to eiiect tuming movement of a wheel and indicating means for indicating the amount of force required to turn the wheel against a braking force applied to the wheel. By testing each of the wheels with my apparatus, the condition of the brakes can be accurately determined and by comparing the braking force applied to the different wheels under similar conditions, the relative jack up the car so driver, upon the,

distribution of the braking force can be readily determined.

Referring now to the drawingfI have shown a brake 'tester comprising a lever having two relatively movable parts, 16 and 17 hingedly securedto one another by a hinge 18. Relative movement'between members 16 and 17 about hinge 18 is opposed by yieldable means, such as a spring 19, one end of which abuts against an abutment member 21 rigidly secured to member 16. The other end of spring 19 engages a collar 22 mounted on a rod 23, one end of which is pivotally connected, as by means of a pivot 24, to an upstanding element 26 rigidly mounted on member 17. The spring 19 is adapted to exert a compres-- sional force between abutm'entmember 21'and collar 22, which through the medium of rod 23 and its connection to element 26 tends to retain the members 16 and 17 in substantial alignment as shown in Figs. 1 and 2.

For convenience, the rod 23 preferably passes through the coils of spring 19 and an aperture 2'7 in the abutment member 21. Upon forcibly moving members 16 and 17 relative to each other about the hinge it}, the distance between the abutment member 21 and the collar 22 is decreased, thereby further compressing spring 19. Duringthis movement, the rod 23 is caused to move longitudinally within the aperture 27 and there is also a relatively slight lateral movement of the rod relative to member 21. To enable movement 0! rod 23 in this manner, the aperture 27 in member 21 is preferably elongated in at least one direction as shown in Fig. 2.

Secured to the remote end of member 1'7 is a members and for holding the same in operative position relative to the automobile Wheel.

When the device has been clamped to a wheel as shown in Fig. 3, turning movement can be imparted to the wheel by a force applied to the handle 34 at the end of member 16. In the arrangement of the parts illustrated in Fig. 3, a force directed downwardly on. the handle 34 will tend to turn the wheel 31 in a counter-clockwise direction. Assuming that there is a force resisting the turning movement of wheel 31, such as a braking force applied to the wheel, the force directed against handle 34 must be sufiicient to overcome the resisting iorce before the wheel will turn. The force applied to handle 34 is transmitted from member 16 to member 17 through the spring 19 by the mechanism heretofore described and spring 19, therefore, will be compressed substantially in proportion to the force applied. During the compression of spring 19, the members 16 and 17 are caused to move relative to one another about hinge l8 and accordingly, this relative movement is also substantially proportional to the force applied to handle 34.

For measuring the extent of movement between members 18 and 17, and also the amount by which the spring 19 has been compressed, thereby determining the force applied to handle 34, one end of rod 23 can be connected to actuating means for an indicating device 36. As representative of suitable means for connecting rod 23 to the indicator 36, I have shown rod 23 as being bent inwardly, as at 37, toward the surface or" member 18 and then extending througha guide member 38 mounted on member 16. A pin 39 secured to the end or" rod 23 passes through a slot ll at one end of a lever 42 which is fillcrurnmed at 43. The other end or lever 42 carries a gear segment a l which meshes with a pinion 46. Rigidly secured to pinion as and adapted to rotate therewith is a pointer 27 cooperating with a graduated dial 48.

Upon compressing the spring 19, rod 23 is caused to move relative to the member 16, thereby actuating lever 42 and its associated gear segment to efiect movement oi pointer e: to indicate the force applied to handle 3%.

In Fig. l, 3 have illustrated an auxiliary device which can be employed for maintaining the brake pedal 51 or" an automobile depressed while the brakes oi the automobile are being tested. In

the particular form or the device illustrated, clamping member 52 is provided which is adapted to be clamped to the post 55 of the steering w or" the automobile, Pivctally connected to end so of the clamping device an arm 53 having a plurality oi teeth 57 which are adapted to en gage the pedal 51 and to retain the in any desired position.

In using the device. the automobile on which the brakes are to be tested is first raised until the wheels are out of contact with the ground. The brake pedal is then partially depressed to apply the brakes relatively lightly and is retained in depressed position by the device illustrated in Fig. l. Clamps 28 and 29 are then secured to one of the wheels and a force is applied to handle 34 which is sufficient to cause the wheel to turn against the braking force. The reading on indicator 36 is noted wh le the force is being applied. Each of the other wheels of the automobile are then tested in the same manner with the same setting of the brake pedal.

If desired, the indicator dial can be calibrated to measure the braking iorce directly, but whether or not it is so calibrated, the relative readings for the different wheels will indicate the relative distribution of the braking force. By tightening the brake bands on those wheels on which the braking power is deficient and by loownhig the brake bands where the braking power is excessive, the brakes on all or" the wheels can be readily adjusted so that they are all equal or so they have any other relative distribution 01' the braking force. For example, wheels can be adjusted to a different value than the brakes on the front wheels, while at the same time keeping the brakes on the right hand side of the car equal in power to the brakes on the left hand side.

Thereafter, the brake pedal canbe actuated to a different position'and all 0! the brakes tested again for the new position and proper adjustments or repairs made until the brakes on all of the brakes on the rearthe wheels have the desired distribution of braking force for any position of the brake pedal.

For accommodating the device to automobile wheels of difierent sizes, clamping members 28 and 29 are preferably made removable so that smaller or larger clamping members can be substituted whenever desired. Also, the rod 23 is preferably provided with a screw thread for receiving an adjusting nut 58 for adjusting the spring 19 to any desired value.

While I have shown and described a preferred embodiment oi my invention, 1 do not wish to be limited thereto, since the invention as defined in the appended claims can be embodied in a plurality of other forms.

I claim:

'1. In a brake testing device the character described, a lever having two relatively movable members placed end to endv in substantial alignment, hinge between said members, yleldable means interconnecting said members and opposing relative movement therebetween, and indi cating means associated with said yieldable means for indicating the force exerted by said lever.

2. In a brake testing device of the character described, a lever having two relatively movable members placed end to end in substantial alignrnent, a hinge between said members, cla ping means mounted on one of said lever for ena wheel whereby turning movement can be imparted to the wheel by actuation of the lever, r lient means interconnecting said movable 2 shore and relative movement therebctween, and an indicating device opera-lively co, nected to lever for indicating t extent relative mov ment between said about said hinge.

3. In a brake testing device the character described, a lever having two relatively movable members placed end to end in substantial alignmerit, a hinge between said members, a spring interconnecting said members and opposing movement off the members about said hinge, means mounted on one end of said lever for engaging a wheel a position to effect turning movement of the wheel when a force is exerted against the other end of said lever, whereby relative movement between said members is effected, and indicating means responsive to the movement of said members for indicatlng the force exerted by said lever in turning the In a brake testing device of the character described, a lever for effecting turning movement of a'wheel against a braking force applied to said wheel, said lever being divided into two par a hinge interconnecting said parts, means mounted on one end of said lever for engaging the rim of the wheel in a position to effect turning movement of the wheel when a force is applied against the other end of the lever, whereby the mechanical advantage afforded by said lever is substantially proportional to the length of the lever increased by the radius of the wheel to which it is applied, a spring interconnecting said two parts of the lever and opposing relative movement therebetween, the force ,exerted against said lever causing relative movement between the two parts of the lever about said hinge substantially proportional to the applied force, and indicating means operatively connected to said lever for indicating the amount or" relative movement and accordingly the applied force.

osoaos A. wsror.

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